Frame structure for folding wheel chair



March 29, 1960 w. E. MlZE 2,930,429

FRAME STRUCTURE FOR FOLDING WHEEL CHAIR Filed March 26, 1956 2 Sheets-Sheet 1 dfi'av/wegg March 29, 1960 W. E. MIZE FRAME STRUCTURE FOR FOLDING WHEEL CHAIR 2 Sheets-Sheet 2 Filed March 26, 1956 FRAME STRUCTURE FOR FOLDING WHEEL CHAIR William E. Mize, Ladoga, Incl, assignor, by mesne assignv rgfiitg to Institutional Industries, Inc., a corporation of Application March 26, 1956, Serial No. 573,811

3 Claims. (Cl. 155-30) This invention relates generally to folding wheel chairs '7 for invalids and more particularly is concerned with a novel frame structure for such wheel chairs.

The conventional folding wheel chair consists of a pair of vertically arranged, laterally spaced side frames fabricated fromtubular metal and permanently interconnected by a collapsible cross-linkage or brace which permits lateral movement of one side frame relative to the other. The distance between side frames when the chair is unfolded or what contributes to the width of the chair seat, is determined by the length of the crossmembers forming said folding linkage or brace. A manufacturer may be required to provide a great variety of models, such as chairs having different widths for the chair seat, or chairs having variations in the side frame structure such as to mount the drive wheels at the front instead of the rear of the chair or to support different types of leg and foot rest supports. chair models require the manufacturer to have different tools, dies, jigs and the like for assembling the different models, and of course, the cost of manufacturing the wheel chairs in a complete line capable of satisfying such varying public demand will be substantially increased.

It is therefore a principal object of the invention to provide a novel frame structure for folding wheel chairs which includes a side frame formed of two separate units and a folding linkage capable of being detachably 'assembled in a manner substantially eliminating the disadvantages hereinabove mentioned.

Another object of the invention is to provide a frame :structure of the character described which will enable advantageous interchanging of said side frames and folding linkage to achieve a standardized assembly for such folding wheel chairs in a great variety of models.

A further object of the invention is to provide a wheel chair frame structure of the character described which enables the same side frames to be employed in manuapparent as the description thereof evolves, in connectionv with which a preferred embodiment of the invention has been described in detail in the specification and illustrated in the accompanying drawings. It is contemplated that minor variations may be made in the size, arrangement, proportion and construction of the several parts of the invention without departing from the scope or sacrificing any of the advantages thereof.

In the drawings, wherein the same reference characters Such variations in V ice Patented Mar. 29, 1960 have been employed to designate the same or equivalent parts throughout the several figures thereof:

Fig. 1 is a side elevational view of an assembled folding wheel chair embodying the principles of the inven: tion.

Fig. 2 is an exploded elevational view showing the relationship of the folding cross-linkage of the invention with respect to one of the side frames of the chair, this rela:

tionship being. identical for the other side frame.

Fig. 3 is a fragmentary front elevational view of a said chair and Fig. 4 is a similar view of the same chair of different width.

Fig. '5 is a sectional view taken through said chair; along the 1ine 5 -5 of Fig. l and in the direction indicated.

Fig. 6 is a'sectional view taken through thechair along the line 6-6 of Fig. 1 and in the direction indi.-

cated. p

Fig. 7 is a sectional view taken along the line 7-- of Fig. 1 and in the direction indicated.

Fig. 8 is a perspective view of the foldable crosslinkage or brace employed in the invention, the cross linkage being shown in combination with the side frame members of a wheel chair to which it is normally connected.

Referring to the drawings, the wheel chair embodying the invention has been designated generally by the reference character 10. Same resembles a conventional wheel chair in external appearance to include a pair of vertically arranged, laterally spaced side frames interconnected by a folding cross-linkage which is novel in construction to permit achievement of the advantages herein enustructure and variations in construction of the side frames required different assembly techniques and equipment. The same applied in the caseiof different chair models for providing variations in the width of the chair seat. These problems are entirely eliminated by means'of the novel frame structure for folding wheel chairs herein after described. p

The novel assembled side frame embodying the invention has been designated generally 16 in Fig.- 1. A pair of side frames 16 are employed in each completed chair, the frames being identical so that description of. one will suflice. Referring to Fig. 2, said side frame 16 is comprised of two principal units designated 18 and 20 respectively, the unit 18 beingpositioned at the front of the chair and unit 20 at the rear thereof. Each of the said unitspreferably is formed of hollow'tubular metal mem-' bers connected together advantageously to provide vertically arranged assemblages.

The unit 18 is comprised'of a pair of vertically spaced, horizontal: straight sections 22 and 24 rigidly secured as =by welding intermediate the ends thereof to a vertical post 26. Secured to the forward or front ends 28 and" 30 respectively of said sections is a leg rest assembly 14, said assembly being angularly offset relative to said' sec-- parent that front unit 18 may be fabricated with a suitable 3 leg rest assembly installed either to provide an adjustable or non-adjustable assembly without varying the basic structure of the unit.

The vertical post 26 comprises the front vertical support post of the chair. The lower end thereof mounts the caster wheel 13 by means of the bearing 31 attached on said lower end in a well known manner. The upper end 32 of said post 26 extends above the horizontal section 22 a short distance and it is preferred said end 32 be open so as to provide a socket for mounting the arm support 11 in accordance with the disclosure of my copending application for an invention entitled, Removable Side Arm Support for Wheel Chairs, filed March 26, 1956 and bearing Serial No. 573,810, now abandoned.

Rigidly secured between the rear ends 34 "and 36 respectively of sections 22 and 24 is one leg 38 of an L-shaped member, the second leg 40 being disposed offset below the section 24 and extending outwardly of said unit 18 or toward the rear of the assembled chair. The leg 38 is secured at its end 41 to the bottom edge of said section 22 so that the end 34 of section 22 is clear and open. The opposite extremity of the leg 38 mounts a hollow fitting 43 in which leg 40 is secured at an end thereof. The outside diameter of leg 40 is less than the outside diameter of leg 38 or section 22. The leg or shaft 40 will be seen to be arranged in a horizontal plane and has a transverse opening 44 therethrough adjacent its free end 45. Likewise a transverse opening 46 is provided through section 22 spaced inwardly of the juncture be tween section 22 and leg 38. As explained, the unit 18 is arranged in a vertical plane at the front of the chair, so that the leg 40 actually extends rearwardly and the end 34 of section 22 opens towards the rear of the completed chair.

The unit 20 comprises an elongate vertical post 48 which comprises the rear vertical support post of the chair. Said post is bent at its upper end to provide a handle 49, the lower end being attached to a hollow fitting 50 perpendicular thereto. The fitting 50 is open at its forward end 52 or toward the front of the chair and closed at its rear end by a resilient shoe or bumper 53. It will be noted that the fitting 50 has the major portion thereof extending rearward from the post 48 to provide a socket opening toward the front of the chair.

Secured intermediate the extremities of said post 48 is a tubular bar54, the bar 54 being secured at one end thereof in 'a substantially horizontal plane and extending oppositely from fitting 50 or toward the front of the chair. Secured to the free end face 56 of said bar is a reduced diameter shank 57 having a transverse opening 58 therethrough adjacent the free extremity 59 thereof.

The vertical distances between the longitudinal axes of the bar 54 and fitting 50 and between the longitudinal axes of the leg 40 and section 22 are equal. The diameter of the shank 57 is sutficient to permit insertion into open end 34 of the section 22 while the diameter of the leg 40 is sufficient to permit insertion into fitting 50. The dimensions of the various parts of said units 18 and 20 are such that upon mating engagement of leg 40 and fitting 50, the respective openings 44 and 51 thereinwill be aligned one with the other, and upon mating engagement of shank 57 with hollow section 22 through open end 34, openings 46 and 58 will be aligned one with the other. Thus, the units-18 and 20 each have 1nwardly facing sockets and complemental inserts which are capable of being telescopically and detachably connected together to complete the side frames of the chair.

The rear unit 20l1as been shown mounting the drive wheelon the vertical support post 48. The upper portion of said post 48 has secured thereto one end of a bracket supportmember60, the other end being secured to the post of the opposite side frame in a well-known manner. In'addit ion, means may be provided on a said post 48 for detachably connecting the arm support 11 at its end opposite to its connection in socket 32 as explained n y said co-pending patent application. Such means have been deemed unnecessary to illustrate in this application. Other means for securing the arm supports are suitable within the scope of the invention.

Referring to Fig. 8, the cross-linkage employed in the invention has been designated generally 62. Same includes a pair of identical laterally spaced end frames of generally rectangular configuration, each end frame providing a pair of horizontally arranged, vertically spaced sections 64 and ,66. The members 66, 66 are each hollow and open at opposite ends thereof, the inside diameter of each being slightly larger than the diameter of the leg 40. The sections 64 are each substantially longer than its opposite section 66 to provide an outwardly or forwardly directed horizontal extension 71. The vertical distance between the longitudinal axes of said sections 64 and 66 is greater than the distance between the longi' tudinal axes of section 22 and leg 40 and bar 54 and fitting 50.

The end frames of said linkage 62 are rigidly secured to the extremities of a pair of cross-braces 72 and 74, said braces 72 and 74 of each said pair being pivotally connected together at their point of crossing by bolts 76 shown in Fig. 2. The cross-braces 72 and 74 are so secured spaced one from the other and short brace members '78 are connected by suitable fasteners between said cross braces 72 and 74 and the vertical struts or posts 60 and 38 of each side frame as seen in Fig. 8. Between each of the top horizontal sections 64 is mounted a fabric member 80 by fasteners 81 providing the seat for the chair. The pivotal connection of said braces 72 and 74 permits lateral movement of the end frames relative to each other.

Referring to Figs. 3 and 4, Fig. 3 shows a completed chair as viewed from the front end thereof having a wider seat 80 than the seat 80a provided on the chair illustrated in Fig. 4, the chairs in each of said figures being otherwise identical. The ditference in width of the said seats 80 and 80a is attained by reason of the different lengths of the cross-braces 72 and 74. Thus, in Fig. 3, the length of cross-braces 72 and 74 is greater than the corresponding cross-braces 72a and 74a of the chair in Fig. 4. Of course, the length of fabric seat 80 is correspondingly greater than fabric seat 8011. It will be apparent that the cross-linkage 62 may be manufactured to provide a linkage capable of providing any desired seat width when the chair is unfolded.

To assemble the chair, theunits18 and 20 of each vertical side frame are aligned one behind the other with the unit 18 at the front. The cross-linkage 62 is interposed between the said units 18 and 20 with the extensions 71 thereof at the top and facing toward unit 20 or the front of the chair. The units and linkage 62 are moved together to pass a leg 40 throupgh each hollow section 66, the length of the leg 40 being greater than section 66 so that the end 45 will protrude outwardly therefrom. The protruding end 45 is then inserted through open end 52 of fitting 50 until openings 44 and 51 are aligned one with the other. A threaded bolt 82 is inserted through said aligned openings 44 and 51 and fastened at its end by a nut 83 in the manner illustrated in Fig. 6. At the same time, the bar 54 will be able to clear the section 64 and extension 71 and permit insertion of shank 57 into opening 34 of section 22 until openings 46 and 58 are aligned, at which time the end face of end 34 will abut the end face 56. A threaded bolt 84 is inserted through said aligned openings 46 and 48 and secured by a nut 85 as. shown in Fig. 7. These nuts 83 and 85 may-consist of lock nutsor suitable lock washers may be utilized in a well known manner not requiring specific illustration or description.

It will be understood thatthe cooperative assembly of the units 18.and 20 and the linkage .62 is identical for each of the vertical side frames of the chair 10. In each case, the sections 64 and extensions 72 will each be spaced above the adjacent detachably interconnected section 22 and bar 54 when the chair is unfolded so that said sections 64 and 72 having the fabric seat 80 sus pended therebetween may be supported on said connected section 22 and bar 54 when a person is seated in the chair.

It will thus be seen that the basic structure of the separate units of the side frame and the folding linkage provides for advantageous interchanging of parts thereof so that a standardized assembly for a great variety of chair models is achieved. Chairs of varying seat widths may be manufactured using the same side frames by merely installing the proper folding linkage from a stock which has been fabricated in different sizes. Where variations in side frames are required, such as for a chair having a non-adjustable leg rest assembly or other variation, the same cross-linkage may be" used for a wide variety of styles. The basic plan of the side frames and folding linkage permitting detachable assembly thereof in the manner described will remain the same. Thus, different assembly techniques and equipment as has been required heretofore where the side frames were of unitary construction and the folding linkage was permanently secured are entirely unnecessary with the accompanying savings in time and cost of manufacture.

Additionally, ease of repair, speed in replacement of parts, and ready modification of the chair are inherent in the structure.

It is believed the invention has been described in sufiicient detail to enable a complete understanding of the principles thereof. It is contemplated that minor departures from the constructional features described in order to contribute to such an understanding will occur to the skilled artisan without departing from the broad principles of the invention as defined in the claims hereto appended.

What it is desired to secure by Letters Patent of the United States is:

1. A frame structure for folding wheel chairs comprising a pair of vertically arranged laterally spaced side frames, a collapsible cross-linkage unit having a flexible chair seat at the upper end thereof, said cross-linkage unit being connected between said side frames to permit lateral movement of one frame relative to the other for folding and unfolding of the chair, each side frame including separate front and rear units having cooperative fastening means for detachably securing the same together to form the said side frame, said cooperative fastening means of each side frame including a horizontal and cylindrical bottom shaft being rigidly secured at one end to one of said front and rear units and being detachably connected at the opposite end thereof to the other of said units of each side frame, said cross-linkage unit also constituting a separate unit and being provided with a pair of horizontal and parallel bottom sleeves each telescopically and rotatably receiving one of said horizontal bottom shafts, said sleeves being freely slidable off of and onto said shafts when said shafts are detached from said 7 other unit of each of said side frames and said front and frames, a collapsible cross-linkage unit having at least two pairs of cross-braces fixed adjacent their lower ends to'a pair of parallel and horizontal sleeves and being provided at their upper ends with a flexible chair seat, said crosslinkageunit being removably installed between said side frames and being collapsible to enable lateral movement of one frame relative to the other for folding and erecting the chair, each side frame including a front and rear structural unit detachably connected together by upper and lower horizontal members, each of said horizontal members being fixed at one end thereof to one of'said front and rear side frame units and being detachably connected at the opposite end thereof to the other of said side frame units, each of said sleeves of said cross-linkage unit telescopingly and rotatably receiving one of said horizontal members provided by one of said side frames and being slidably removable from said member upon disconnection and separation of the front and rear units thereof, whereby, said structural units and linkage units may be interchangeably assembled to'form a variety of chair models.

3. A frame structure for a folding wheel chair comprising a pair of side frames each having detachable front and rear units, said side frames providing a pair of elonbraces, a pair of parallel and horizontal tubular sleeves each being securely fixed to the lower ends of corresponding braces of said respective pairs, .each of said lower horizontal members extending through and rotatably suporting a single tubular sleeve of said folding linkage unit, and a pair of parallel seat-supporting members having a foldable fabric seat extending therebetween, said seat-supporting members being securely fixed only to the upper ends of said braces of the folding linkage unit, said sleeves being slidably removable from said lower horizontal members when said opposite ends of said members are released from said socket and said front and rear units are separated.

References Cited in the file of patent UNITED STATES PATENTS 2,181,420 Everest et al. Nov. 28, 1939 2,379,566 Duke July 3, 1945 2,402,085 Rideout June 11, 1946 a 2,486,015 I Everest et a1 Oct. 25, 1949 2,570,446 Hofiman Oct. 9, 1951 2,601,379 Everest et al. June 24, 1952 2,675,057 Glass Apr. 13, 1954 2,769,483 Peterson Nov. 6, 1956 FOREIGN PATENTS 92,471 Austria May 11, 1923 

